Apparatus and method for managing radio resource in wireless communication system

ABSTRACT

The present disclosure relates to a pre-5 th -Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4 th -Generation (4G) communication system such as Long Term Evolution (LTE). Embodiments herein provide a method implemented in a User Equipment (UE). The method includes receiving, from a Mobility Management Entity (MME), a bearer resource modification reject message with a cause value, in response to a bearer resource modification request message sent to the MME. Further, the method includes deactivating an Evolved Packet System (EPS) bearer context information.

CROSS-REFERENCE TO RELATED

This application is a continuation of application Ser. No. 15/154,878,filed May 13, 2018, which claims priority under 35 U.S.C. § 119(a) to anIndian Provisional Patent Application filed on May 14, 2015 in theIndian Intellectual Property Office and assigned Serial No.2443/CHE/2015, and an Indian Complete Patent Application filed on Apr.26, 2016 in the Indian Intellectual Property Office and assigned SerialNo. 2443/CHE/2015, the entire contents of each of which are incorporatedherein by reference.

BACKGROUND 1. Field

The subject matter of the present disclosure relates to wirelesscommunication, and more particularly to apparatus and method formanaging radio resource in wireless communication system.

2. Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4G (4th-Generation) communication systems, efforts havebeen made to develop an improved 5G (5th-Generation) or pre-5Gcommunication system. Therefore, the 5G or pre-5G communication systemis also called a ‘beyond 4G network’ or a ‘post LTE system’.

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission distance, the beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques are discussed in5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), reception-endinterference cancellation and the like.

In the 5G system, hybrid FSK and QAM modulation (FQAM) and slidingwindow superposition coding (SWSC) as an advanced coding modulation(ACM), and filter bank multi carrier (FBMC), non-orthogonal multipleaccess (NOMA), and sparse code multiple access (SCMA) as an advancedaccess technology have been developed.

The introduction of Internet Protocol (IP) Multimedia Subsystem (IMS)has resulted in the increased usage of dedicated bearers, especially forvoice calls and video calls. The frequent establishment and release ofthe bearers also accompanies with the modification, addition, ordeletion of packet filters. These results in increased possibility ofpacket filter content conflicts in a User Equipment (UE) side. The 3rdGeneration Partnership Project (3GPP) specification 24.301 describesabout the scenario of packet filter mismatch or overlap (precedence,filter Identification (ID), or the like) and in such mismatch cases, theUE should accept the filters on a new bearer and delete the conflictingfilters of the old bearer. The latter has to be updated to a networkthrough a bearer resource modification request.

Further, the 3GPP specification states that the UE synchronizes thebearers with the network, after any local changes in the packet filters,through the bearer resource modification request. But, the specificationdoes not describe the UE actions in case the bearer resourcemodification request is rejected by the network.

In response to the bearer resource modification request, the failure ofthe “Bearer Resource Modification” via “Bearer Resource ModificationReject” or “Evolved Packet System (EPS) Status” message from the networkresults in the bearer still being active on the UE side. Since thepacket filters were deleted on the UE side (most of the times, all thefilters related to the bearer), the bearer is no longer used to transmitany packets in the UE side. Since the bearer is still active in the UEside, the IMS client in UE continues to transmit data related to thebearer, which is in-turn not sent from a modem, due to deletion of thepacket filter. The other possibility is that even if the packets aresent on the default bearer, the same will be dropped at a PrimaryGateway (P-GW). This continues, till the release of the specific bearerby the network.

Further, if the UE transmit the Bearer Resource Modification Request tothe network in order to release all the resources in the bearer, thenetwork would normally respond by initiating a deactivation procedurefor the context, but the network transmits Bearer Resource ModificationReject with cause value #31. The 3GPP specification does not specifywhat would be the correct UE action in such a case which means after therejection the UE may have a useless EPS bearer context that cannot bereleased. This will lead to various problems in the UE such as datastall with respect to the bearer for which the UE has deleted allTraffic Flow Template (TFT) packet filters. If the bearer is related toaudio call it will lead to call mute issue. If the bearer is related tothe video call then the screen will be blank, or the like which degradesthe user experience.

Consider a scenario: if a user of the UE initiates a Voice over LongTerm Evolution (VoLTE) audio call, the network assigns the dedicatedbearer for the audio which includes packet filters for the audio. ThenUE upgrades the audio call to a video call. After upgrading the audiocall to the video call, the network assigns dedicated bearer for thevideo which includes the packet filter for the video. Due to somechanges on the network side, the network transmits a bearer resourcemodification request message for the audio bearer (includes new set ofpacket filters for the audio) to the UE. However, the packets receivedas part of bearer resource modification request message for the audiobearer has conflict (i.e., packet filter mismatch) with existing packetfilters assigned for the video bearer. In such case, as per 3GPPspecification, the UE accepts newly received packet filters and deletesthe existing packet filters of the video bearer. The UE informs the sameto the network through the bearer resource modification request with anOP CODE set as DELETE for the video bearer. If the network rejects thebearer resource modification request, the video bearer will not receiveany data and video will be stuck since the packets filters for the videobearer has been deleted at the UE side. In such case, the video bearerwill neither receive the video data nor is it released on the UE.

Consider another scenario: if the user of the UE initiates a VoLTE audiocall. The network assigns the dedicated bearer for the audio whichincludes packet filters for the audio. The UE upgrades the audio call tothe video call. The network assigns the dedicated bearer for the videowhich includes the packet filter for the video. Due to some changes onthe network side, the network transmits the bearer resource modificationrequest for the video bearer which includes new set of packet filtersfor the video. However, the packets received as part of bearer resourcemodification request for the video bearer has conflict (i.e., packetfilter mismatch) with existing packet filters assigned for the audiobearer. In such case, as per 3GPP specification, the UE accepts thenewly received packet filters and deletes the existing packet filters ofthe audio bearer. The UE informs the same to the network through thebearer resource modification request with the OP CODE set as DELETE forthe audio bearer. The packet filter of the audio bearer is deleted atthe UE. The deleted audio bearer information is not updated to thenetwork as the network transmits the bearer resource modification rejectmessage to the UE. Since the packet filters are deleted, the audiobearer will not receive any data and audio will be mute.

Consider another scenario: an Application “A” requests required Qualityof Service (QoS) and the network assigns dedicated bearer for theApplication “A”. Application “B” also requests required QoS, and thenetwork assigns the dedicated bearer for the Application “B”. Due tosome changes on the network side, the network transmits the bearerresource modification request for the Application “B” which includes newset of packet filters for the Application “A”. However, the packetsreceived as part of the bearer resource modification request for theApplication “A” have conflict (i.e., packet filter mismatch) with theexisting packet filters assigned for the application “A”. In such case,as per 3GPP specification, the UE accepts newly received packet filtersand deletes the existing packet filters of the Application “A”. The UEinforms the same to the network through the bearer resource modificationrequest with OP CODE set as DELETE for the audio bearer. If the networktransmits the bearer resource modification reject message to the UE, thepacket filter of Application “A” Bearer is deleted at the UE. Thedeleted packet filter is not updated to the network as the network sentthe bearer resource modification reject to the UE. Thus, the Application“A” bearer will not receive any data and data stall will be observed forthe Application “A”.

The above information is presented as background information only tohelp the reader to understand the present disclosure. Applicants havemade no determination and make no assertion as to whether any of theabove might be applicable as Prior Art with regard to the presentapplication.

SUMMARY

To address the above-discussed deficiencies, it is a primary object toprovide a method an apparatus implemented by a User Equipment (UE) todeactivate an Evolved Packet System (EPS) bearer context locally when abearer resource modification reject message is received from a Network.

Another object of the embodiments herein is to provide a method and anapparatus for transmitting a Tracking Area Update (TAU) request messagewith EPS bearer context status to a network to synchronize the EPSbearer context with the network.

Embodiments herein disclose a method implemented in a User Equipment(UE). The method includes receiving, from a mobility management entity(MME), a bearer resource modification reject message with a cause value,in response to a bearer resource modification request message sent tothe MME. The method further includes deactivating an evolved packetsystem (EPS) bearer context information based on the cause value.

The method further includes transmitting a Tracking Area Update (TAU)request message with EPS bearer context status to the MME to synchronizethe EPS bearer context with the MME.

The cause value refers to an EPS Session Management (ESM) cause valueindicating “request rejected, unspecified”.

Embodiments herein disclose a User Equipment (UE) apparatus. Theapparatus includes is configured to receive, from a mobility managemententity (MME), a bearer resource modification reject message with a causevalue, in response to a bearer resource modification request messagesent to the MME. The UE is further configured to deactivate an evolvedpacket system (EPS) bearer context information based on the cause value.

Embodiments herein disclose a method implemented in a MME. The methodincludes generating a bearer resource modification reject message with acause value, in response to a bearer resource modification requestmessage received from the UE; and transmitting, to the UE, the bearerresource modification reject message with the cause value, wherein anevolved packet system (EPS) bearer context information is deactivatedbased on the cause value.

Embodiments herein disclose an apparatus implemented in a MME. Theapparatus includes a controller configured to generating a bearerresource modification reject message with a cause value, in response toa bearer resource modification request message received from the UE; anda transmitter configured to transmit, to the UE, the bearer resourcemodification reject message with the cause value, wherein an evolvedpacket system (EPS) bearer context information is deactivated based onthe cause value.

These and other aspects of the embodiments herein will be betterappreciated and understood when considered in conjunction with thefollowing description and the accompanying drawings. It should beunderstood, however, that the following descriptions, while indicatingpreferred embodiments and numerous specific details thereof, are givenby way of illustration and not of limitation. Many changes andmodifications may be made within the scope of the embodiments hereinwithout departing from the spirit thereof, and the embodiments hereininclude all such modifications.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document: the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation; the term“or,” is inclusive, meaning and/or; the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like; and the term “controller”means any device, system or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware orsoftware, or some combination of at least two of the same. It should benoted that the functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely.Definitions for certain words and phrases are provided throughout thispatent document, those of ordinary skill in the art should understandthat in many, if not most instances, such definitions apply to prior, aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 is a flow diagram illustrating a method of deactivating anEvolved Packet System (EPS) bearer context locally when a User Equipment(UE) receives a bearer resource modification reject message from anetwork, according to the embodiments as disclosed herein;

FIGS. 2 to 6 are sequence diagrams illustrating step by step procedurein deactivating an EPS bearer context locally when a UE receives abearer resource modification reject message from a network, according tothe embodiments as disclosed herein;

FIG. 7 is illustrating the UE apparatus according to an exemplaryembodiment of the present disclosure; and

FIG. 8 is illustrating the network apparatus according to an exemplaryembodiment of the present disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 8, discussed below, and the various embodiments used todescribe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged telecommunication technologies.

The embodiments herein and the various features and advantageous detailsthereof are explained more fully with reference to the non-limitingembodiments that are illustrated in the accompanying drawings anddetailed in the following description. Descriptions of well-knowncomponents and processing techniques are omitted so as to notunnecessarily obscure the embodiments herein. Also, the variousembodiments described herein are not necessarily mutually exclusive, assome embodiments can be combined with one or more other embodiments toform new embodiments. The term “or” as used herein, refers to anon-exclusive or, unless otherwise indicated. The examples used hereinare intended merely to facilitate an understanding of ways in which theembodiments herein can be practiced and to further enable those skilledin the art to practice the embodiments herein. Accordingly, the examplesshould not be construed as limiting the scope of the embodiments herein.

The embodiments herein achieve a method implemented in a User Equipment(UE). The method includes receiving a bearer resource modificationreject message from a Mobility Management Entity (MME) with a causevalue in response to a bearer resource modification request message sentto the MME. The method further includes deactivating an Evolved PacketSystem (EPS) bearer context locally in response to the bearer resourcemodification reject message.

In an embodiment, the method further includes transmitting a TrackingArea Update (TAU) request message with the EPS bearer context status tothe MME to synchronize the EPS bearer context with the MME.

In an embodiment, the cause value refers to an EPS Session Management(ESM) cause value that indicates request rejected, unspecified.

Consider the scenario: if the UE transmit the bearer resourcemodification request message to the network in order to release all theresources in the bearer, the network would normally respond byinitiating a deactivation procedure for the bearer, but the networktransmits a bearer resource modification reject message along with cause#31. The cause #31 corresponds to the ESM cause value #31 “requestrejected, unspecified”. After receiving the bearer resource modificationreject message along with the cause #31 by the UE, the UE deactivatesthe EPS bearer context locally without peer-to-peer signaling betweenthe UE and the MME in the network. In order to synchronize the EPSbearer context status with the MME, the UE transmits the TAU requestmessage that includes the EPS bearer context status Information Element(IE) to the MME.

Unlike the conventional methods, the proposed method minimizes thewastage of resources on the UE side and ensures quicker synchronizationof bearer states on the UE and the network. This results in providing abetter user experience. The method handles a bearer resource releasefrom the UE side. The proposed method is easy to implement on the UEwithout any modification in the network. The method handles Traffic FlowTemplate (TFT) conflict scenarios in a video call and an audio call.

The method avoids a call mute issue, if the bearer is related to theaudio call. The method avoids a screen blank issue, if the bearer isrelated to the video call. The method avoids a data stall problem withrespect to the bearer for which the UE has deleted all TFT packetfilters.

Referring now to the drawing, and more particularly to FIGS. 1-6, thereare shown preferred embodiments.

FIG. 1 is a flow diagram illustrating a method 100 for deactivating theEPS bearer context locally when the UE receives the bearer resourcemodification reject message from the network, according to theembodiments as disclosed herein. The steps 102 to 108 are performed by aprocessor (e.g. microprocessor, microcontroller, or the like) of the UE.The UE can be, for example but not limited to, a cellular phone, a smartphone, a mobile phone, a tablet, a laptop, a Personal Digital Assistant(PDA), or the like.

At step 102, the method 100 includes transmitting the bearer resourcemodification request message to the MME. At step 104, the method 100includes receiving the bearer resource modification reject message fromthe MME with the cause value.

In an embodiment, the cause value refers to the ESM cause value thatindicates request rejected, unspecified.

In an example, the cause value is ESM cause value #31.

At step 106, the method 100 includes deactivating the EPS bearer contextlocally. At step 108, the method 100 includes transmitting the TAUrequest message with the EPS bearer context status to the MME tosynchronize the EPS bearer context with the MME.

The proposed method 100 minimizes the wastage of resources on the UEside and ensures quicker synchronization of bearer states on the UE andthe network side. This results in providing the better user experience.The proposed method 100 is easy to implement on the UE without anymodification in the network. The method 100 handles the bearer resourcerelease from the UE side. The method 100 handles the TFT conflictscenarios during the voice call and the audio call.

Consider an example, if the user of the UE initiate's a Voice over LongTerm Evolution (VoLTE) audio call, the network assigns the dedicatedbearer for the audio which includes packet filters for the audio. The UEupgrades the audio call to a video call. After upgrading the audio callto the video call, the network assigns dedicated bearer for the videowhich includes the packet filter for the video. Due to some changes onthe network side, the network transmits the bearer resource modificationrequest message for the audio bearer (includes new set of packet filtersfor the audio) to the UE. However, the packets received as part ofbearer resource modification request message for the audio bearer hasconflict (i.e., packet filter mismatch) with existing packet filtersassigned for the video bearer. In such case, as per 3GPP specification,the UE accepts newly received packet filters and deletes the existingpacket filters of the video bearer. The UE informs the same to thenetwork through the bearer resource modification request with the OPCODE set as DELETE for the video bearer. If the network rejects thebearer resource modification request, the UE deactivates the EPS bearercontext locally without peer-to-peer signaling between the UE and thenetwork. Further, in order to synchronize the EPS bearer context statuswith the MME, the UE transmits the TAU request message that includes theEPS bearer context status to the network. Thus, this example results inavoiding the call mute issue and improving the user experience.

Consider another example: if the user of the UE initiates the VoLTEaudio call. The network assigns dedicated bearer for the audio whichincludes packet filters for the audio. The UE upgrades the audio call tothe video call. The network assigns the dedicated bearer for the videowhich includes the packet filter for the video. Due to some changes onthe network side, the network transmits the bearer resource modificationrequest for the video bearer which includes new set of packet filtersfor the video. However, the packets received as part of bearer resourcemodification request for the video bearer has conflict (i.e., packetfilter mismatch) with existing packet filters assigned for the audiobearer. In such case, as per 3GPP specification, the UE accepts thenewly received packet filters and deletes the existing packet filters ofthe audio bearer. The UE informs the same to the network through thebearer resource modification request message with the OP CODE set asDELETE for the audio bearer. If the networks transmits the bearerresource modification reject message to the UE, the UE deactivates theEPS bearer context locally without peer-to-peer signaling between the UEand the network. Further, in order to synchronize the EPS bearer contextstatus with the network, the UE transmits the TAU request message thatincludes the EPS bearer context status to the network. Thus, thisexample results in improving the user experience.

Consider another example: an Application “A” requests required Qualityof Service (QoS) and the network assigns dedicated bearer for theApplication “A”. Application “B” also requests required QoS, and thenetwork assigns the dedicated bearer for the Application “B”. Due tosome changes on the network side, the network transmits the bearerresource modification request for the Application “B” which includes newset of packet filters for the Application “A”. However, the packetsreceived as part of the bearer resource modification request for theApplication “A” has conflict (i.e., packet filter mismatch) withexisting the packet filters assigned for the Application “A”. In suchcase, as per 3GPP specification, the UE accepts newly received packetfilters and deletes the existing packet filters of the Application “A”.The UE informs the same to the network through the bearer resourcemodification request with OP CODE set as DELETE for the audio bearer. Ifthe network transmits the bearer resource modification reject message tothe UE, the UE deactivates the EPS bearer context locally withoutpeer-to-peer signaling between the UE and the network. Further, in orderto synchronize the EPS bearer context status with the network, the UEtransmits the TAU request message that includes the EPS bearer contextstatus to the network. This results in improving the user experience.

The various actions, acts, blocks, steps, or the like in the method 100may be performed in the order presented, in a different order orsimultaneously. Further, in some embodiments, some of the actions, acts,blocks, steps, or the like may be omitted, added, modified, skipped, orthe like without departing from the scope of the disclosure.

FIGS. 2 to 6 are sequence diagrams illustrating a step by step procedurein deactivating the EPS bearer context locally when the UE 102 receivesthe bearer resource modification reject message from the network 104,according to the embodiments as disclosed herein.

As shown in the FIG. 2, the UE 102 transmits (202) the bearer resourcemodification request message to the network 104. In an embodiment, thebearer resource modification request message includes the Op Codecontaining the DELETE TFT. The network transmits (204) the bearerresource modification reject message to the UE 102. Based on the bearerresource modification reject message, the UE 102 locally releases (206)the bearer context information and triggers the TAU procedure. Further,the UE 102 transmits (208) the TAU with the EPS bearer information tothe network 104. The network 104 transmits (210) the TAU accept responsemessage to the UE 102. Based on the TAU accept response message, thebearer context information is synchronized (212) in the UE 102 and thenetwork 104.

In an embodiment, the bearer information indicates to the network 104about the bearer that the UE 102 released locally (inactive) and thebearer that is still active in the UE 102.

In an example, the UE 102 releases the audio bearer locally and retainsthe video bearer. The EPS bearer information indicates to the network104 that the inactive audio bearer and the active video bearer.

As shown in the FIG. 3, the UE 102 transmits (302) the bearer resourcemodification request message to the network 104. In an embodiment, thebearer resource modification request message includes the Op Code withthe DELETE TFT. The network transmits (304) the bearer resourcemodification reject message along with the cause value to the UE 102. Inan embodiment, the cause value refers to the ESM cause value thatindicates the request rejected, unspecified status. In an example, thecause value is ESM cause value #31. Based on the bearer resourcemodification reject message along with the cause value, the UE 102locally releases (306) the bearer context information. The network 104locally releases (308) the bearer context information.

In an embodiment, the network 104 locally releases the bearer contextinformation first and then UE 102 locally releases the bearer contextinformation.

In an embodiment, the bearer context information indicates to thenetwork 104 about the bearer that the UE 102 released locally (inactive)and the bearer that is still active in the UE 102.

In an example, the UE 102 releases the audio bearer locally and retainsthe video bearer. The EPS bearer information indicates to the network104 that the inactive audio bearer and the active video bearer.

As shown in the FIG. 4, the UE 102 transmits (402) the bearer resourcemodification request message to the network 104. In an embodiment, thebearer resource modification request message includes the Op Codecontaining the DELETE TFT. The network transmits (404) the ESM statusmessage along with the cause value to the UE 102. In an embodiment, thecause value refers to the ESM cause value that indicates the requestrejected, unspecified status. In an example, the cause value is ESMcause value #31. Based on the ESM status message along with the causevalue, the UE 102 locally releases (406) the bearer context informationand triggers the TAU procedure. Further, the UE 102 transmits (408) theTAU with the EPS bearer information to the network 104. The network 104transmits (410) the TAU accept response message to the UE 102. Based onthe TAU accept response message, the bearer context information issynchronized (412) in the UE 102 and the network 104.

In an embodiment, the bearer context information indicates to thenetwork 104 about the bearer that the UE 102 released locally (inactive)and the bearer that is still active in the UE 102.

In an example, the UE 102 releases the video bearer locally and retainsthe video bearer. The EPS bearer information indicates to the network104 that the inactive video bearer and the active video bearer.

As shown in the FIG. 5, The UE 102 transmits (502) the bearer resourcemodification request message to the network 104. In an embodiment, thebearer resource modification request message includes the Op Codecontaining the DELETE TFT. The network transmits (504) the ESM statusmessage along with the cause value to the UE 102. In an embodiment, thecause value refers to the ESM cause value that indicates the requestrejected, unspecified status. In an example, the cause value is ESMcause value #31. Based on the ESM status message along with the causevalue, the UE 102 locally releases (506) the bearer context information.The network 104 locally releases (508) the bearer context information.

In an embodiment, the network 104 locally releases the bearer contextinformation first and then the UE 102 second locally releases the bearercontext information.

In an embodiment, the bearer context information indicates to thenetwork 104 about the bearer that the UE 102 released locally (inactive)and the bearer that is still active in the UE 102.

In an example, the UE 102 releases the audio bearer locally and retainsthe video bearer. The EPS bearer information indicates to the network104 that the inactive audio bearer and the active video bearer.

As shown in the FIG. 6, in an embodiment, the UE 102 includes an IMSclient 106 and a Non-Access Stratum (NAS) layer 108. In an embodiment,the network 104 includes the MME 110, a Primary Gateway (P-GW) 112, andIMS NW 114. The NAS layer 108 transmits (602) the bearer resourcemodification request message to the MME 110. The MME 100 transmits (604)the bearer resource modification reject message or the ESM statusmessage along with the cause value to the NAS layer 108. In anembodiment, the cause value refers to the ESM cause value that indicatesthe request rejected, unspecified status. In an example, the cause valueis ESM cause value #31. After receiving the bearer resource modificationreject message or the ESM status message along with the cause value bythe NAS layer 108, the NAS layer 108 locally releases (606) the bearerand informs to the IMS client 106. Further, the NAS layer 108 transmits(608) the TAU with the EPS bearer information to the MME 110. The MME110 transmits (610) the TAU accept message to the NAS layer 108. Afterreceiving the TAU accept message by the NAS layer 108, the NAS layer 108transmits (612) the bearer release indication to the IMS client 106. TheIMS client 106 informs (614) corresponding to the bearer releaseindication to an IMS core. Further, the bearer context information issynchronized (616) with the UE 102 and the network 104.

In an example, when the UE 102 initiated modification for the videobearer is rejected by a Long Term Evolution (LTE) network. When the UE102 initiates modification to delete the video bearer, then the videocall will indicate release of the video bearer. Further, the UE 102deletes the packet filters and inform to the IMS client 106. The IMSclient 106 transmits a RE-INVITE to the LTE network for downgrading thevideo call to the voice call. This will trigger the network 104 toinitiate a graceful release the video bearer. This avoids a scenariowhere the user would have seen a blank screen with only the voiceongoing for the video call.

In another example, when the UE 102 initiated modification for the audiobearer is rejected by the LTE-Advanced (LTE-A) network 104. The modemwill indicate the release of the audio bearer to the IMS client, afterthe deletion of the packet filter. The UE 102 transmits a BYE to theLTE-A network for disconnecting the call. This will again result inimmediate synchronization of the bearer on the UE 102 and LTE-A networksides, since the LTE-A network initiates release of the audio bearer.This also avoids a scenario where the call would have been dropped dueto a Real-time Transport Protocol (RTP) time-out.

Although exemplary embodiments of the present disclosure have beendescribed in detail hereinabove, it should be understood that manyvariations and modifications of the basic inventive concept hereindescribed, which may be apparent to those skilled in the art, will stillfall within the spirit and scope of the exemplary embodiments of thepresent disclosure.

The embodiments disclosed herein can be implemented through at least onesoftware program running on at least one hardware device and performingnetwork management functions to control the elements. The elements shownin the FIGS. 1 to 6 include blocks, elements, actions, acts, steps, orthe like which can be at least one of a hardware device, or acombination of hardware device and software module.

FIG. 7 is illustrating the UE apparatus according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 7, the UE includes transmission unit 700 (e.g., atransmitter), reception unit 710 (e.g., a receiver), and controller 720.The transmission unit 700 and reception unit 710 respectively include atransmission module and a reception module for communicating with thenetwork according to an exemplary embodiment of the present disclosure.The reception unit 710 receives the bearer resource modification rejectmessage with a cause value from the network.

The controller 720 locally deactivates an evolved packet system (EPS)bearer context information in response to the bearer resourcemodification request message.

The transmission unit 700 transmits the TAU request message with EPSbearer context status to the MME to synchronize the EPS bearer contextwith the MME.

FIG. 8 is illustrating the network apparatus according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 8, the network includes transmission unit 800 (e.g., atransmitter), reception unit 810 (e.g., a receiver), and controller 820.The transmission unit 800 and reception unit 810 respectively include atransmission module and a reception module for communicating with the UEaccording to an exemplary embodiment of the present disclosure. Forexample, the transmission unit 800 transmits the bearer resourcemodification reject message with a cause value to the UE.

The controller 820 generates the bearer resource modification rejectmessage with a cause value.

The reception unit 810 receives the bearer resource modification requestmessage including the cause value from the UE.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the embodiments herein that others can, byapplying current knowledge, readily modify and or adapt for variousapplications such specific embodiments without departing from thegeneric concept, and, therefore, such adaptations and modificationsshould and are intended to be comprehended within the meaning and rangeof equivalents of the disclosed embodiments. It is to be understood thatthe phraseology or terminology employed herein is for the purpose ofdescription and not of limitation. Although the present disclosure hasbeen described with an exemplary embodiment, various changes andmodifications may be suggested to one skilled in the art. It is intendedthat the present disclosure encompass such changes and modifications asfall within the scope of the appended claims.

What is claimed is:
 1. A method for a user equipment (UE), the methodcomprising: transmitting, to a mobility management entity (MME), abearer resource modification request message for releasing all trafficflows for a bearer; receiving, from the MME, a bearer resourcemodification reject message with a cause value; deactivating an evolvedpacket system (EPS) bearer context locally without peer-to-peersignaling between the UE and the MME, in response to receiving thebearer resource modification reject message; and transmitting, to theMME, a tracking area update (TAU) request message comprising an EPSbearer context status information element (IE) to synchronize an EPSbearer context status with the MME, wherein the cause value indicatesthat a request is rejected for at least one of unspecified reasons. 2.The method of claim 1, wherein the EPS bearer context status issynchronized in the UE and the MME.
 3. The method of claim 1, whereinthe EPS bearer context status IE indicates that at least one EPS bearercontext is active within the UE.
 4. An apparatus for a user equipment(UE), the apparatus comprising: a transceiver; and at least oneprocessor coupled to the transceiver, wherein the at least one processoris configured to: transmit, to a mobility management entity (MME), abearer resource modification request message for releasing all trafficflows for a bearer, receive, from the MME, a bearer resourcemodification reject message with a cause value, deactivate an evolvedpacket system (EPS) bearer context locally without peer-to-peersignaling between the UE and the MME, in response to receiving thebearer resource modification reject message, and transmit, to the MME, atracking area update (TAU) request message comprising an EPS bearercontext status information element (IE) to synchronize an EPS bearercontext status with the MME, and wherein the cause value indicates thata request is rejected for at least one of unspecified reasons.
 5. Theapparatus of claim 4, wherein the EPS bearer context status issynchronized in the UE and the MME.
 6. The apparatus of claim 4, whereinthe EPS bearer context status IE indicates that at least one EPS bearercontext is active within the UE.
 7. A method for a mobility managemententity (MME), the method comprising: receiving, from a user equipment(UE), a bearer resource modification request message for releasing alltraffic flows for a bearer; transmitting, to the UE, a bearer resourcemodification reject message with a cause value; and receiving, from theUE which deactivated an evolved packet system (EPS) bearer contextlocally without peer-to-peer signaling between the UE and the MME, atracking area update (TAU) request message comprising an EPS bearercontext status information element (IE) to synchronize an EPS bearercontext status with the MME, wherein the cause value indicates that arequest is rejected for at least one of unspecified reasons.
 8. Themethod of claim 7, wherein the EPS bearer context status is synchronizedin the UE and the MME.
 9. The method of claim 7, wherein the EPS bearercontext status IE indicates that at least one EPS bearer context isactive within the UE.
 10. The method of claim 7, further comprising:transmitting, to the UE, a TAU accept message to accept asynchronization of the EPS bearer context status with the UE.
 11. Anapparatus for a mobility management entity (MME), the apparatuscomprising: a transceiver; and at least one processor coupled to thetransceiver, wherein the at least one processor is configured to:receive, from a user equipment (UE), a bearer resource modificationrequest message for releasing all traffic flows for a bearer, transmit,to the UE, a bearer resource modification reject message with a causevalue, and receive, from the UE which deactivated an evolved packetsystem (EPS) bearer context without peer-to-peer signaling between theUE and the MME, a tracking area update (TAU) request message comprisingan EPS bearer context status information element (IE) to synchronize anEPS bearer context status with the MME, and wherein the cause valueindicates that a request is rejected for at least one of unspecifiedreasons.
 12. The apparatus of claim 11, wherein the EPS bearer contextstatus is synchronized in the UE and the MME.
 13. The apparatus of claim11, wherein the EPS bearer context status IE indicates that at least oneEPS bearer context is active within the UE.
 14. The apparatus of claim11, wherein the at least one processor is further configured to:transmit, to the UE, a TAU accept message to accept a synchronization ofthe EPS bearer context status with the UE.